new lens produces blurry results

[wamoz]

I take pictures with a 1950’s view camera (4x5). A while ago, I purchased a (new) Rodenstock Apo Sironar S 135mm lens. I took a series of landscape photos, had a photo lab develop the film, and then was diverted from processing/printing for a few months. When I did finally print, all the shots (about 14) were blurry as if I had focused badly. Now, I’m capable of missing focus some of the time—but not all. I’m thinking that the problem is NOT a lens defect; if that were the case, the problem wouldn’t be an out-of-focus effect, but some more obvious anomaly in the image field. I’m wondering if somehow I’m placing the front lens of the lens assembly at an incorrect distance from the rear lens. I might have done this by accidentally substituting the rear lens of another of my 135 mm lens assemblies for the one that came with the Rodenstock. I also note that there is a space ring between the lensboard and the rear lens; could I have substituted that from another lens? Does the Rodenstock assembly have a spacer ring (the ring may have come from my 135mm Schneider lens). Anyhow, the Rodenstock is unusable as is. Anyone have any ideas?

[E. von Hoegh]

First, sort out any mismatched lens parts, then check that the groundglass is positioned properly. There is much useful info on the LFPF homepage, you can get there by clicking on "LF Home Page" in the upper left corner.

[ic-racer]

Is it still under warranty?

[IanG]

Is it still under warranty?

Not if the rear cells been switched

You need to try and ascertain if the cells have got muddled, that may not be easy, however the Symmras are Symmetrical and most Sironars aren't so that may help, it would also cause much greater problems if you do have a mismatch.

For a short time Schneider sold Symmars that would take a combination of front & rear cells, you can do this with some symmetrical lenses, a bit like a casket set.

My Rodenstock lenses with spacers have beeen on the fornt cell where it screws into the shutter, sometimes lenses have aring beteween shutter & lens board that's quite different.

Ian

[ic-racer]

Not if the rear cells been switched

If you did send it back for warranty service, I'd think they should be able to determine if it has the wrong rear cell and let you know the mistake.

[John Kasaian]

Why would you take apart a brand new and unused lens and switch around the cells between a Rodenstock & Schneider?

[turtle]

Look at a bunch of photos of this lens online and determine if something funny is going on.

Rule out any changes to the camera set up and so some tests to isolate the problem as the lens.

[Leigh]

I have that same lens, and it's tack sharp.

There is no "spacer ring" between the lensboard and any part of the lens.
There is a retaining ring that holds the shutter in place when mounted on the lensboard.

There could be/have been a spacer on the threaded end of the rear cell, where it mounts to the rear of the shutter.
If so, it should have been removed with the rear cell when you mounted the shutter on the board, then re-installed.

If the lens was not focusing properly due to some physical problem you would notice that with a loupe on the ground glass.

Any rear lens cell that was originally mounted on a Copal #0 shutter could be substituted for the original one on this lens,
but why would that happen in the first place? And you would certainly notice the problem while focusing.

I'm inclined to think your ground glass is not positioned correctly relative to the actual film plane as defined by the holders.

Does the problem occur with all holders? ... with other lenses?

Are the film holders seated properly in the back of the camera?
Is any portion of the image in focus, particularly toward the edge of the film opposite the notches?

- Leigh